Junction-box.



Patented Apr. 9, l90l.

E. T. GREENFIELD.

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PATEN EDWIN T. GREENFIELD, OF NEWV YORK, N. Y.

JUNCTION-BOX.

SPECIFICATION formingpart of Letters Patent No. 671,762, dated April 9, 1901.

To all whom it may concern.-

Be it known that I, EDWIN '1. GREENFIELD, a citizen of the United States, residing at New York, in the borough of Manhattan, county and State of New York, have made a new and useful Invention in Junction-Boxes, of which the following is a specification;

My invention has for its objects, first, to provide a junction-box with inleading necks or inlets which shall not offer any roughened or angular surface to the insulation of electrical conductors when drawn therethrough; and, second, to provide a junction-box with inleading necks or inlets which shall not offer any roughened or angular surface to the insulation of electrical conductors when drawn therethrough, and also to provide means whereby the ends of tubular conduits may be secured thereto without screw-threading the same.

Existing rules of the National Board of Fire Underwriters in the United States require that in the wiring of buildings in which the Wires are protected by interior or house conduits and metallic junction-boxes there shall be offered no abrading or tearing surfaces to the insulating-surfaces of conductors when drawn therethrough when placing the same in For the purpose of complying with these rules it has heretofore been customary to insert bushings or sleeves in the necks or inlets of junction-boxes, the inner ends of which bushings are flared or of bell-mouth shape, said bushings being usually secured in place by screw-threads in the inlets of the junction-boxes, or else provided with screwthreads at their exterior ends to which the conduit pipes or tubes are attached by corresponding screw-threads. My improvement is designed to accomplish the same result by so constructing a junction-box that the beforementioned bushings may be entirely elimited and will be understood by referring to the accompanying drawings, in which Figure 1 is a plan view of a junction-box embodying my improvement, the cover of the junction-box being broken away at the lower left-hand corner for the purpose of more fully illustrating the same, two short sections of conduit pipes or tubes being also illustrated in connection therewith. Fig. 2 is a sectional view taken on the broken line a: m, Fig. 1, and

Serial No. 49,564. (No model.)

as seen'looking thereat in the direction of the arrows from the bottom toward the top of the drawings, a part of the junction-box and one of the conduit pipes or tubes being shown in elevational view.

Referring now to the drawings in detail,-B B represent a metallic junction-box made, preferably, in two parts, provided with outwardly-extending half-necks N N N, the arrangement being such that when the two parts of the box are secured together by screws, as shown in Fig. 1, tubular inlets are provided for the inner ends of the conduit pipes or tubes P P to be connected with the box, the structure being in this general respect not materially different from thejunction-box disclosed in a prior patent, No. 665,676, granted to me on the 8th day of January, 1901. With the present improvement, however, the inner surfaces of the half-necksN are flared or bellmouthed, as shown at S, Fig. 1, so as to present a smooth non-abrading surface to the conductors as they are drawn through the conduit pipes or tubes P and into the boxes. The exterior inner portion of the half-necks N are of larger bore, as shown at A, for the purpose of acting as a seat for the abutting ends of the conduit pipes or tubes P, this bore being preferably of a diameter greater than the inner bore of the necks N, equal to the thickness of the metal of which the pipes or tubes P are composed, thereby offering an interior diameter of the tubes and the necks which is continuous, and therefore offers no abrading-surface, as clearly illustrated in Fig. 2.

s s are set-screws, one or more for each neck N, adapted to constitute means for securing the ends of the conduit pipes or tubes P in position. With such an arrangement I avoid the necessity of threading the ends of the conduit pipes or tubes P at the time the wiring is being done in a building, thereby saving very materially in expense and labor. It will also be further understood that With such an arrangement I am enabled to make the necks of the junction-boxes of lighter material than is possible with structures where it becomes necessary to screw-thread them either exteriorly or interiorly, thereby making an important saving in material.

I have illustrated at the lower side of the drawings in Fig. 1 how my improvement may be adapted for use in connection with flexible armored conduits like those disclosed in prior patents heretofore granted to me and now largely in public use, T representing the enlarged screw-threads corresponding to the spiral screw-threaded armor of the beforementioned flexible armored conduits.

I do not limit my invention to the especial details of construction hereinbefore disclosed and illustrated in the accompanying drawings, as it might be departed from in numerous ways and still come within the scope of my claims hereinafter made. .To illustrate, instead of constructing thejunction-boxes so that they and the necks of the inlets are made in two parts they might be constructed so that the entire necks are integral with a complete box, such junction-boxes being well known and in general use.

'Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is-

l. A junction-box provided with outwardly extending necks integral with the box, the inner surfaces whereof are flared or bellmouthed; in combination with means for securing conduit pipes or tubes thereto, substantially as described.

2. A junction-box provided with-outwardly extending necks integral with the box, the inner surfaces whereof are flared or hellmouthed, the exterior inner portion of said necks being of larger diameter and adapted or tubes, when in position, shall be iiush with the inner bore of the necks, substantially as described.

3. A junction-box provided with outwardlyextending necks integral with the box, the inner surfaces whereof are flared or hellmouthed, the exterior inner portion of said necks being of larger diameter and adapted to receive the ends of conduit pipes or tubes so that the inner surfaces of said conduit pipes or tubes, when in position, shall be flush with the inner bore of the necks; in combination with means for rigidly securing the conduit pipes ,or tubes and the necks together, substantially as described.

4. A junction-box constructed in two parts with half-necks flared or bell-mouthed at their inner ends and having an interior bore at their outer ends of increased diameter, substantially as described. I

5. A junction-box constructed in two parts with half-necks flared or bell-mouthed at their inner ends and having an interior bore at their outer ends of increased diameter for receiving the ends of conduit pipes ortubes in combination with means for firmly uniting the conduit pipes or tubes to the necks, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDWIN T. GREENFIELD. 

